/Engine/Plugins/Online/OnlineSubsystem/Source/Public/Interfaces/OnlineChatInterface.h
Delegate used when another chat room member is updated
typedef TMulticastDelegate_ThreeParams< void, const [FUniqueNetId](API\Runtime\CoreOnline\Online\FUniqueNetId) &, const [FChatRoomId](API\Plugins\OnlineSubsystem\Interfaces\FChatRoomId) &, const [FUniqueNetId](API\Runtime\CoreOnline\Online\FUniqueNetId) & > FOnChatRoomMemberUpdate